convert remaining scattering examples

auto/Examples/fit/scatter2d/custom_objective_function.py

auto/Examples/fit/scatter2d/find_background.py

auto/Examples/fit/scatter2d/fit_along_slices.py

auto/Examples/fit/scatter2d/fit_with_masks.py

auto/Examples/fit/scatter2d/lmfit_basics.py

auto/Examples/fit/scatter2d/lmfit_with_plotting.py

auto/Examples/fit/scatter2d/model1_cylinders.py

auto/Examples/fit/scatter2d/model2_hexlattice.py

auto/Examples/fit/scatter2d/multiple_datasets.py

auto/MiniExamples/fit/scatter2d/custom_objective_function.py

auto/MiniExamples/fit/scatter2d/find_background.py

auto/MiniExamples/fit/scatter2d/fit_along_slices.py

auto/MiniExamples/fit/scatter2d/fit_with_masks.py

auto/MiniExamples/fit/scatter2d/lmfit_basics.py

auto/MiniExamples/fit/scatter2d/lmfit_with_plotting.py

auto/MiniExamples/fit/scatter2d/model1_cylinders.py

auto/MiniExamples/fit/scatter2d/model2_hexlattice.py

auto/MiniExamples/fit/scatter2d/multiple_datasets.py

rawEx/fit/scatter2d/custom_objective_function.py

rawEx/fit/scatter2d/find_background.py